After printing the code for the lesson, everything is printed as it should be, but I get an error stating that:

“It looks like the sum of grades was not printed! Make sure you are printing it on its own line.”

Other than that error message, everything appears to be working correctly. I even calculated everything manually to make sure the printed information was correct and it was, so I don’t know why it doesn’t like the information that was printed. The output is as follows:

Grades:

40

50.5

65

70

80

85

85

90

90

90

100

100

100

Sum of grades: 1045.5

Average grade: 80.4230769231

Grade variance: 334.071005917

Standard deviation: 18.2776094147

```
grades = [100, 100, 90, 40, 80, 100, 85, 70, 90, 65, 90, 85, 50.5]
grades = sorted(grades)
def print_grades(grades_input):
print "Grades:"
for grade in grades_input:
print grade
print
def grades_sum(grades_input):
grade_sum = 0
for grade in grades_input:
grade_sum += grade
return grade_sum
def grades_average(grades_input):
sum_new = grades_sum(grades_input)
print
return sum_new/float(len(grades_input))
def grades_variance(scores):
average = grades_average(scores)
variance = 0
for score in scores:
variance += (average-score) ** 2
variance /= len(scores)
return variance
def grades_std_deviation(variance):
return variance ** 0.5
print_grades(grades)
print "Sum of grades: {}".format(grades_sum(grades))
print "Average grade: {}".format(grades_average(grades))
print "Grade variance: {}".format(grades_variance(grades))
print "Standard deviation: {}".format(grades_std_deviation(grades_variance(grades)))
```